| 摘要: | 由過去的研究顯示吸菸或二手菸暴露者的修補基因多型性與DNA損傷的相關性呈現不一致的結果。本研究欲探討暴露於菸害之孕婦其修補基因多型性和DNA損傷的相關性，並進一步分析菸害暴露與修補基因多型性對DNA損傷是否具有交互作用。
以自願者方式徵求來自台中兩家醫學中心與ㄧ家區域醫院之參加產前檢查的懷孕婦女為研究對象。對孕婦進行問卷調查、可丁寧濃度測量、基因型分析及彗星試驗，總共有237名孕婦納入本次研究。以尿液、血液測量可丁寧濃度。以聚合酶鏈鎖反應（PCR）與限制酵素片段長度多型性（RFLP）對修補基因：XRCC1 (Arg399Gln)、XRCC3 (Thr241Met)、XPD (Lys751Gln) 和hMLH1 (promoter G to A) 做基因型檢測。以彗星試驗 (comet assay) 測量DNA損傷的程度。
參與本研究的懷孕婦女共有237名的資料可供分析。非吸菸者有102名（43％）、二手菸者有118名（49.8％）、吸菸者有17名（7.2％）。以孕婦尿液、血液進行分析，血液可丁寧平均濃度在吸菸組為2.11 ng/ml，二手菸組為1.02 ng/ml，非吸菸組為0.62 ng/ml，尿液可丁寧平均濃度在吸菸組為2.36 ng/ml，二手菸組為2.25 ng/ml，非吸菸組為1.42 ng/ml，血液及尿液中可丁寧濃度均隨著非吸菸、二手菸、吸菸之暴露程度增加而有上升的趨勢。以彗星試驗測量孕婦DNA損傷的程度，DNA損傷積分的平均值在吸菸組為77.7，二手菸組為83.4，非吸菸組為65.2，顯示吸菸組與二手菸組之DNA損傷程度皆比非吸菸組高。
修補基因hMLH1 A / A或G / A基因型之DNA損傷程度是G / G基因型的2.83倍，且達到統計上顯著意義 ( OR =2.83 ; 95％ CI：1.13－7.05)，經過調整年齡、血清可丁寧濃度、尿液可丁寧濃度、喝酒習慣、香菸暴露狀態等變項後，修補基因hMLH1 A/A或G/A基因型之DNA損傷程度是G/G基因型的3.49倍，亦達到統計上顯著意義 ( aOR = 3.49 ; 95％ CI：1.32－9.24)。四種修補基因隨著各個基因之變異型數目增加，DNA損傷程度會增加，當個體單一個修補基因帶有變異型之DNA損傷積分平均值，在吸菸組為68.6，二手菸組為74，非吸菸組為64.3，吸菸組與二手菸組之DNA損傷程度皆比非吸菸組高；當個體的修補基因有二個及二個以上同時帶有變異型之DNA損傷積分的平均值，在吸菸組為84.1，二手菸組為96，非吸菸組為69.4，吸菸組與二手菸組之DNA損傷程度皆比非吸菸組高，且達到統計上顯著意義 (p = 0.002)。特別是暴露於二手菸的狀態下，個體修補基因有二個及二個以上同時帶有變異型之DNA損傷積分的平均值為96，比單一個修補基因帶有變異型的74還要高，且達到統計上顯著意義 (p = 0.021)。
本研究顯示暴露於二手菸或吸菸的孕婦所誘發的DNA損傷比非吸菸者高。hMLH1基因型可能調控吸菸或二手菸的暴露狀態與DNA損傷程度之間的相關性。吸菸或二手菸暴露且帶有修補基因變異型的孕婦對DNA損傷可能具有加成作用。
The purpose of this study was two folded. First, we examined the possible effect of cigarette smoking and environmental tobacco smoke (ETS) on the health of pregnant women, by measuring cotinine concentrations and comet assay. Second, the correlations of repair gene polymorphisms and genotoxicity of gestation women were analyzed.
With consented, pregnant women participated prenatal care at two medical centers and one regional hospital in central Taiwan were recruited in this study. The subjects were to complete a questionnaire, cotinine measuring, genotyping and comet assay. Two hundreds thirty-seven pregnant women were included in this research. The urine and serum cotinine concentrations were measured. Polymerase chain reaction - restriction fragment length polymorphisms (PCR-RFLP) method was utilized to determine XRCC1, XRCC3, XPD and hMLH1 genotypes. DNA damage was measured by comet assay.
The 237 pregnant participants included 102 (43%) non-smokers, 118 (49.8%) passive smokers, and 17 (7.2%) smokers. The level of serum cotinine was 2.11±1.89 ng/ml in smokers, 1.02±1.81 ng/ml in passive smokers, 0.62±1.11 ng/ml in non-smokers. The level of urine cotinine was 2.36±2.94 ng/ml in smokers, 2.25±3.15 ng/ml in passive smokers, 1.42±2.19 ng/ml in non-smokers.The findings indicated that the cotinine levels in serum and urine elevated significantly as the exposure to ETS and smoking increased. The DNA damage value was 77.7±51.6 in smokers, 83.4±45.5 in passive smokers, and 65.2±34.9 in non-smokers, and the level of DNA damage among the ETS group was significantly higher than that of non-smoking group (p < 0.001).
The value of DNA damage among women with hMLH1 A/A or G/A genotypes was significantly higher than subjects with G/G genotype (OR = 2.83; 95% CI: 1.13-7.05) (aOR = 3.49; 95% CI: 1.32-9.24). Combined gene effects upon DNA damage were observed. The DNA damage value was 68.6±47.5 in smokers, 74±43.5 in passive smokers, and 64.3±32.2 in non-smokers for the pregnant woman had one variant genotype. The DNA damage value was 84.1±55.8 in smokers, 96±44.5 in passive smokers, 69.4±35.9 in non-smokers for the pregnant woman had more than two or equals two variant genotypes. The level of DNA damage among the pregnant woman with more than two variant genotypes in ETS group was significantly higher than that of the non-smoking group (p = 0.002). The level of DNA damage among the pregnant woman with more than two variant genotypes was higher than that with one variant genotype, especially in ETS group (p = 0.021).
In conclusion, the level of DNA damage among the smoking and ETS groups was significantly higher than that of non-smoking group. hMLH1 A/A or G/A genotypes may modify the association between Smoking or ETS-exposed and DNA damage. Exposed to smoking and carring at least two variant genotypes among XRCC1, XRCC3, XPD, hMLH1 may be associated with DNA damage in pregnant women. |
